Abstract: A multi-layer blood culture sensor includes two matrices. The first matrix is a polymer that is permeable to carbon dioxide and water, but impermeable to protons. A pH sensitive absorbance based dye is encapsulated or isolated in the polymer. The second matrix is a polymer with a pH insensitive fluorescent dye encapsulated or isolated in the polymer. The matrices are spectrally coupled and are useful for the determination of microorganisms in a blood culture bottle.

Abstract: A process to determine the concentration of any substance in a colorimetric, turbidimetric or nephelometric reaction using a fluorometric detector to measure fluorescence intensity. In particular, a change in color can be monitored by observing the measurement of fluorescence intensity of a fluorophore in an inert matrix. The absorption spectrum of the chromophore may overlap the excitation and/or emission spectrum of the fluorophore, thereby allowing the change in fluorescence to be related to the intensity of color in the reaction and thus related to the quantity of the substance of interest.